In the nuclear power plant industry, the continuous monitoring, repair, and maintenance of the plant by personnel results in thousands of sets of soiled Protective Clothing (PCs) per day. These PCs are biologically soiled and radioactively contaminated. This high volume of contaminated clothing requires round-the-clock laundering service.
There are presently two laundering options: (1) Dry cleaning, and (2) Water Wash.
Dry Cleaning Method:
There are several distinct disadvantages to using the dry cleaning method.
1. The dry cleaning method used to be popular because it produced small amounts of radioactive waste material to be disposed of. However, early in 1989 the U.S. Environmental Protection Agency classified dry cleaning fluids as hazardous chemicals. Any hazardous chemical that contains radioactivity is classified as "mixed waste". Mixed wastes are not accepted at Radiation Waste Disposal Sites. Therefore, radioactive dry cleaning wastes must be stored forever at the facility where they are generated.
2. Dry cleaning fluids are less efficient in the presence of moisture in removing soils, odors, and radioactive contamination. PCs have a lot of perspiration in them from very warm work areas, and multiple layers of clothing. The perspiration does not evaporate because the PCs are sealed in plastic bags immediately upon removal.
3. The workers who wear the PCs complain of the offensive odor. The same dry cleaning fluid is used over and over again for several loads before being distilled and recycled. Many facilities that use dry cleaning also routinely use water wash just to remove the unpleasant odor.
4. Dry cleaning also may cause damage to elastic and other synthetic parts of the protective clothing.
5. Repeated use of dry cleaning of PCs may cause skin irritations in the workers who wear them.
6. The evaporation of dry cleaning fluids into the atmosphere has been determined to be harmful to the ozone layer. Considerable amounts of dry cleaning fluids evaporate in the routine dry cleaning process.
Water Wash Method Without Reclamation:
1. One method has been to use fresh water for each laundry load (approximately 80 to 140 gallons). This produces tens of thousands of gallons of waste effluent per day. This contaminated waste effluent must be disposed of. Disposing of such huge quantities of waste water is extremely costly.
2. A second method is to use the same wash water for a number of loads before disposing of it. Some filtering done between loads removes only a little of the radioactive contamination, some of the macro particles, and none of the bacteria or soap. This method is an attempt to reduce the huge quantities of waste requiring disposal. However, this method compromises the quality of the cleaning of the PCs both biologically and radiologically. This method still results in thousands of gallons per day of waste effluent.
3. An option for disposing of waste effluent is steam evaporation. This method reduces the volume of water to a small amount of sludge. However, this method is prohibitively expensive because of equipment cost and the high cost of energy.
4. Many facilities simply dilute the contaminated waste water to maximum allowable concentrations, and dump it in nearby oceans, lakes or rivers. While this is acceptable under contemporary regulations, it does nothing to reduce the total amount of radioactive waste released into the environment.
The objects and advantages of the present invention are:
1. to provide a quantum significant reduction in the volume of radioactive waste requiring disposal;
2. to provide a modular system, so that it can be either portable and easily relocatable, or housed in a permanent structure;
3. to provide a low-cost alternative to other laundry methods which will give the customer added savings in the form of:
a. a reduction of turn-around time for fresh uniforms, thereby avoiding the delays experienced by shipping to a remote processing operation; PA0 b. a reduction in stockpiles of uniforms in excess of daily inventory usage requirements because of the shorter turn-around time; PA0 c. improved control over the inventory minimizing much of the loss and replacement cost of uniforms; PA0 d. waste residues which do not contain hazardous chemicals and are accepted at the radioactive waste disposal sites. PA0 a. fresher smelling clothing; PA0 b. no damage to elastics and other synthetic materials in the clothing; PA0 c. fewer skin irritations;
4. to provide laundry facilities with the ability to give higher quality of cleaning by using fresh wash water for each load, which will result in
5. to provide laundry facilities with the ability to be water efficient, to thereby save one of our world's diminishing resources.
While the present invention is described primarily in the context of treatment of laundry materials contaminated with radioactive materials, it should be recognized that it is also useful in generating ion-free water for use in hospital laundries, in processing of semiconductor materials, and in manufacture and processing of medical materials.